Stabilization of n,n&#39; di-secondarybutyl p-phenylene diamine



Patented Apr. 17, 1951 UNITED STATES PATENT, oFFicE" STABILIZATION OFN,N' DI-SECONDARY- p BUTYL p-BHENYLENE DIAMINE q Joseph A. Ghenicek,Riverside, Ill., assignor to Universal Oil Products Company, Chicago,111., a corporation of Delaware No Drawing. Application March 27, 1947,Serial No. 737,717

6 Claims. (Cl. 260-577) v for use without the necessity of adding aninhibitor.

Aryl amino compounds are utilized for many purposes, such asintermediates in the preparation of various chemical compounds or asadditives to hydrocarbons or other organic materials. In many cases thediscoloration of amino compounds is undesirable and renders the aminocompounds unsatisfactory for the desired use.

The present invention is particularly applicable for preventingdiscoloration of various amino compounds added to unstable organicmaterials as inhibitors to prevent oxidative deterioration of theorganic compounds. For example, particularly effective inhibitorscomprise N-I Tdi-alkyl p-phenylene diamines and N-alkyl p-aminophenolsbut these inhibitors tend to undergo disprising an aryl amino compoundand an aliphatic aldehyde. i

Various well known inhibitors which have been proposed heretofore forother uses, such aspre venting discoloration or gumming in gasolines,have proved unsatisfactory for preventing the discoloration of arylamino compounds and in some cases these compounds have actuallyaccelerated the discoloration of the amino compound. I have discoveredthat the compounds of the present inventionare effective in preventingdiscoloration of amino'compounds. I

The compounds of the present invention are particularly advantageous inthat they are read- 7 pounds include propionaldehyde, butyraldehyde,

coloration in the presence of oxygen-containing gases such as air.

Another class of aryl amino compounds to which the present invention isparticularly applicable comprises Xylidine and similar type com poundswhich are used as additives to hydrocarbons and particularly gasoline inorder to improve the antiknock characteristics thereof.

In a broad embodiment the present invention relates to a'method ofpreventing the discoloration of amino compounds which comprises addingthereto a small but effective amount of an aldehyde.

In a specific embodiment the present invention relates to a method ofpreventing discoloration of N-N-dialkyl p-phenylene diamines whichcomprises adding thereto from about 0.01% to about 5% by weight of analiphatic aldehyde.

In another specific embodiment the present invention relates to a methodof preventing discoloration of N-alkyl p-aminophenols which comprisesadding thereto from about 0.01% to about 5% by weight of an aliphaticaldehyde.

In another embodiment the present invention relates to a novelcomposition of matter comily available, are relatively inexpensive, aremiscible with aromatic; amino. compounds and do. not adversely aiiectthe inhibiting potency of the amino compounds when the latter are usedas oxidation inhibitors in organiccompounds. :In' addition, thealdehydes of the present invention are readily miscible in organiccompounds, and particularly hydrocarbons, to which the amino compoundsare added as oxidation inhibitors.

The stabilizing compounds of the present invention comprise aldehydesand preferablyaliphatic aldehydes, including both the saturated andunsaturated aldehydes. Preferred stabilizing comvaleraldehyde,heptaldehyde, etc. as representa: tive of saturated aliphatic aldehydes,and citral;

citronellal, etc. as representative of unsaturated aliphatic aldehydes.Aromatic aldehydes include benzaldehyde, salicylaldehyde, vanillin,camphor, etc. It is understood that the various stabilizing compoundswhich may be-utilizedin accordance with the present invention are notnecessarily exactly equivalent in their effectiveness in retarding thediscoloration of amino compounds The stabilizing compounds of thepresent invention will generally be employed in amounts of from 0.01% toabout 5% by weight of the amino compound. In most cases the aldehydewill be added to the amino compound to stabilize the same while instorage and prior to use, although it is understood that, when desired,the aldehyde may be added to organic materials containing the aminocompound.

The following examples are introduced to illustrate further the noveltyand utility of the'present invention but not with the intention ofunduly limiting the same.

Varibus aldehydes were added in an amount of 1% by weight to differentsamples of a gasoline inhibitor comprising N-N'-di-secon.darybutylp-phenylene diamine. V

2,549,056 V V r 4 The samples were stored in 4 oz. bottles andconsisting of n-butyraldehyde, citronella, heptalexposed to the airthrough a oneinch length of dehyde, citral and benzaldehyde. 0.5 mm. I.D. capillary tubing inserted in the 2. N-N'-di-secondary butyl pphenylene distopper. The N. P. A. color was determined in aaminecontaining from about 0.01% to about 5% Union colorimeter after definiteperiods by weight of heptaldehyde. storage at room temperature. 3. 'N- Ndi-secondary-butyl p-phenylene di- XAMP 7 V amine containing from about0.01% to about E E 5 by Weight of n-butyraldehyde. The P'phenylene 1? 4.A 'method of preventing discoloration of amine used'in this examplereached an N. P. A. N N' di secondary butyl p pheny1ene diamine color of8 in 19 hours. The results of the addi. 'w gmp' gs adding t t from abouttion of two aldehydes to different samples of the 0 1%. g a u 5% byWeight of an aldehyde p'phenylene diamine are nd ca ed bfi Qw selectedfrom the group consisting of n-butyral- 7 Table 1 dehyde, citronella,heptaldehyde, citral and V V ben'zaldehyde. V

5. A method of preventing discoloration of N.P.A.Gl Aft r H the N-Ndi-secondary-butyl p-phenylene diamme Adam which comprises addingthereto from about 0 2 19 43 07 91 163 0.01% to about 5% by weight ofheptaldehyde. 20 6. A method of preventing discoloration of N939? 7--.-Y-.--- N-N -di-secondaryrbu yl peu en e ami nputymldehyd 7 1 7% 8which comprises adding thereto from about O1trone1la1 5 6% 7/ 7% 8 8 i Vp. v r 9.91% to about 5% by weight of n-butyraldehyde. It will be notedthat n-butyraldehyde increased JOSEPH CHENICEK' the time of storage toreachari N.'P'. A. color not reater than 8 fromTl9' hours to '163' hoursREFERENCES CITED ci mn lla i eas it??? 'P IW fi m l The followingreferences are of record in the t0 9 191 .5: file or this patent:' f

30. UNITED STATES PATENTS Another sample of N-N-di-secondary-buty lNumber Name D p-phenylene diamine was stabilized with various 1 919 a sDec." 1 1933 aldehydes- Thi sa 9 q@ 1547575 Bond Feb.'20,1934 butylpphenylene diamine was prepared under Id 2 24 D y Ju 12; 93 rdifi'elentco I lditiOIlS than the sample 0f p- 3" 2 249 352 Fitch 1 '1'5' 1941 hel e d a u e n x le 1 a a 2,323,948 V Bramer iqJmy 13, 1943 moreresistant to color change in the presence 3 915 v E t Au 7, 945 ofair.This particular sample required 210 hours before reaching a N. P. A.color of 8. The T R REFERENCES results of these tests are indicated inthe follow- Backstrom, J. Am. Chem. Soc vol. 49, pp. in}; table. V1460-1472(1927).

N: l: 9 1 w iews fe the Following Number of w 4 2 4 120 ts 186 210 232306 ,330 ago 402 475 4% 5 5 5% 6 5% 7 7 7% 4% 4% 5 6 s 6% 7 7% 7 H s s4% 4% 1% 5% 5% 5 6 6% 7% 1% 7% a 8 5 5 e 7 7 7% s noted that the5iioiis'"i1hiie5eivdtii stabilize even the highly resistantamiiiocompgngdmsgdmthemexntexampleyt I claim as my invention: 7 Mannich et al.,Ber. Deut. Chem., vol. 69, pp. l l. N N'--di-'-'econdary butylp-phenylene di- 2106 2123 (1936)] H V amine containing from about0.01%toaboiit 5% Singleton et al., J. Am. Chem. $0 0., vol. 62 up,

y ee 1 were $9P a? ew 288- 2 1

1. N-N''-DI-SECONDARY BUTYL P-PHENYLENE DIAMINE CONTAINING FROM ABOUT0.01% TO ABOUT 5% BY WEIGHT OF AN ALDEHYDE SELECTED FROM THE GROUPCONSISTING OF N-BUTYRALDEHYDE, CITRONELLA, HEPTALDEHYDE, CITRAL ANDBENZALDEHYDE.